The invention relates to a chuck for receiving tools which can be used by rotation about their axis, in particular screwdriver inserts, having an insertion portion having a receiving cavity which has a cross-sectional area that is not round, in which receiving cavity the tool can be secured by means of a holding element associated with the wall of the cavity against being pulled out of the receiving cavity, which holding element can be deactivated by a sliding movement of an actuating member, in particular in the form of an actuating sleeve, the tool being supported at the rear in the receiving cavity.
Chucks of this type are described by DE 29 34 428 and DE 199 32 369. In those documents, the polygonal portion of a bit is fitted into a polygonal bore in an insertion portion. A holding element which is formed by a ball acts on the outer surface of the bit, in particular on its edge or edge cutout. The ball is pressed radially inward onto a polygonal flank or into the corner cutout by an inclined flank of an actuating sleeve. The force required is supplied by a compression spring which spring loads the actuating sleeve and counter to the spring force of which the sleeve is displaced in the release direction.
A magnet which forms the base of the receiving cavity is provided to augment the holding force. In particular short and thin bits can only be removed from the chuck with difficulty counter to the force of the magnet.